The ECPA Bestsellers Lists rank the bestselling books published by ECPA members from the previous month, as reported to NPD BookScan (formerly Nielsen Bookscan) by these reporting retailers.

NPD is purveyor of data, analytics, and consumer insights for the book business, as well as many other businesses such as consumer packaged goods, toys, fashion, digital gaming, and more around the world.

The ECPA Bestseller Lists are compiled using adult book sales data from Christian retail stores across the U.S. A book must have sales in at least 20% of reporting stores during at least one week of the represented reporting cycle to be placed on the list. Only Trade Paper, Cloth and Mass Market Paper books are reported, tracts, mini-books or booklets are not included on this list. Only books which are offered to Christian stores at a trade discount from a publisher or wholesaler are featured on the list. Seasonal/holiday books are omitted from this list.